for many of the ring closing metathesis reactions the driving factor was the formation of ethylene. Interestingly, for this reaction the driving factor was the formation of cyclopentene. Suggest an arrow-pushing mechanism for this reaction. OTBS OPMB Ru OTBS OPMB +

:$:$:$;$$:$$:$

Select the method that would be successful in producing the product starting from the given reactant in good yield Note: The steps in a method are written in the order carried out. EtO OEI mutlistep (a)LIAIH4.(b)H₂O.(c)CH3CH₂CH₂l. OH (a)NaOEt,(b)CH3CH₂CH₂l.(c)NaOEt,(d)CH3CH₂l,(e)H₂O*/heat O(a)LIAIH4. (b)H₂O, (c)NaOEt, (d)CH3CH₂CH₂l, (e)H3O*/heat (a)NaOEt, (b)CH3CH₂CH₂I.(c)NaOEt,(d)CH3l.(e)H3O*/heat

(a) In an acid-catalyzed hydration, one of the following 10 carbon alkynes is expected to produce a single hydration product? Select the correct alkyne and draw the structure of the hydration product that is formed from this alkyne. (I) 2-decyne; (II) 3-decyne; (III) 4-decyne; (IV) 5-decyne; (V) none of these will give a single hydration product. (b) The reaction shown below gives Compound X as the major product. The mass spectrum of X is shown. Br2, H20 Compound X 100 - MS-IW-5644 80 60 40 - 20 - 20 40 60 80 100 120 140 160 180 200 220 m/z Considering the reactions of alkynes and the MS data, de duce which of following structures corresponds to X: Br Br HO, IV V I II II Support your answer with a reaction mechanism for fomation of X and identification of relevant peaks in the mass spectrum. 12 Relative Intensity

Please explain too with mechanism if possible.

Please give the main substitution product for each of the following reactions, and indicate the dominant mechanism:      (a)     1-bromopropane   +   NaOCH3   →      (b)     3-bromo-3-methylpentane   +   NaOC2H5   →

МЕСНANISMS 1,2-epoxy-1-methylcyclopentane undergoes both acid-catalyzed and base-catalyzed opening of the epoxide ring to form two different products. > Using ethanol as the solvent and an appropriate acid, show the steps in the acid catalyzed mechanism, writing structures for all products of the steps. Circle the major product(s). > Using ethanol as the solvent and an appropriate base, show the steps in the base- catalyzed mechanism, writing structures for all products of the steps. Circle the major product(s). 1,2-epoxy-1-methylcyclopentane CH3

I'm curious, can a decyclization or some chemical reaction to eliminate sulfur take place here, possibly forming SO2? and besides that, I would like you to give me examples of deciclizations of heterocycles, if they are possible, I honestly don't know

HO HO Ме— „Me `NH2 H2 F G (d) What type of mechanism is involved in this reaction? Explain the abbreviation used. (e) Would Me-F react with F in the same way? Explain. (f) Why does the N react with Me-l in preference to the O or any of the C atoms?

Provide the E2 mechanism for β-elimination reactionemploying 2-chloro-2-methylbutane to prepare 2-methyl-2-butene and 2-methyl-1-butene reaction. Use the actual structures of thereactants and products. Explain which of the alkenes is the major product ofthis reaction ?